Such devices are generally known. The drilling cutters form a rotating movement with which they scrape parts of the bottom of the hole to be formed. These cuttings are then removed by for example the drilling fluid.
When however a hole has to be drilled into a geological formation of a relatively hard material, this scraping action is very slow and has a low yield.
To alleviate this disadvantage drilling devices are known which use the same principle as a hammer drill. In such a device a bit part is rotated and a hammer part is hammered against this bit part. The vibrations caused by the hammering of the hammer part cause cracks into the material in which the hole is drilled. The rotating bit then scrapes off the cracked parts of the material. A disadvantage of such a device is that the cutters have to endure high forces because of the hammering resulting in an excessive wear of the drill cutters. Another disadvantage is that part of the hammering energy is absorbed in the contact surface between drill bit and hammer part.
Yet another disadvantage is that the cuttings are not adequately removed as no scraping action is performed during lift-off of the bit part.
A further disadvantage is that when sharp cutters are used, which will penetrate the formation, the cutters will hinder rotation of the drilling device.